fix all warnings

rust/src/webserver/webserver.rs

@@ -214,7 +214,7 @@ fn set_config(
     let config: PlantControllerConfig = serde_json::from_slice(&all)?;
 
     let mut board = BOARD_ACCESS.lock().expect("board access");
-    board.board_hal.set_config(config);
+    let _ = board.board_hal.set_config(config);
     anyhow::Ok(Some("saved".to_owned()))
 }